Full opening standing valve installation for bottom hole pump



Sept.'13, 1960 c. J. COBERLY FULL OPENING STANDING VALVE INSTALLATION FOR BOTTOM HOLE PUMP 4 Sheets-Sheet 1 Filed June 9, 1958 ameE/vcs ass/91.

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Sept. 13, 1960 c. J. COBERLY FULL OPENING STANDING VALVE INSTALLATION FOR BOTTOM HOLE PUMP Filed June 9, 1958 4 Sheets-'Sheet 3 5y 1 /15 Jrraxewsys I 2 V ,Herexs; 16750-1, .Fgfse (5%29/5? United States Patent Ofihce FULL OPENING STANDING VALVE INSTALLA- TION FOR BOTTOM HOLE PUlVIP Clarence .l. 'Coberly, San Marino,

-Kobe, Inc., Huntington Park, Califl, a corporation of California Filed June 9, 1958, Ser. No. 740,951 7 Claims. (Cl. 103-219) The present invention relates in general to a standing valve installation for a bottom hole pump and, more particularly, to a standing valve installation for a fluid operated, bottom hole pump of the so-called free type, wherein the pump is removable from the well by displacing it upwaxrdly through a pump tubing string hydraulically by means of operating fluid under pressure supplied to the pump tubing string below the pump through another tub ing string of the tubing system, the pump being seated on a standing valve assembly at the lower end of the pump tubing string when it is in its operating position in the well.

In prior fluid operated, free pump systems, such as that disclosed in my Patent No. 2,338,903, granted January 11, 1944, or that disclosed in my Patent No. 2,589,671 granted March 18, 1952, the standing valve as sembly is supported by an annular seat adjacent the lower end of the pump tubing string which has an inside diameter considerably less than the maximum outside diameter of the standing valve assembly so as to provide proper support for such assembly. The seat for the standing valve assembly in prior standing valve installations thus acts as a restriction preventing the passage through the pump tubing string into the well of equipment for repairing or reconditioning the well, such as equipment for bailing, swabbing, shooting, washing, acidizing, or the like. Consequently, when such repairing or reconditioning operations are necessary with conventional standing valve installations, the tubing system must be pulled from the well, which is time consuming and expensive, irrespective of whether the tubing system is a so-called open system requiring two tubing strings, as disclosed in my Patent No. 2,338,903, or a so-called closed system requiring three tubing strings, as disclosed in my Patent No. 2,589,671.

A primary object of the present invention is to provide a standing valve installation wherein the annular seat for the standing valve assembly has an inside diameter substantially equal to the outside diameter of the standing valve assembly so that any well repairing or reconditioning equipment which is capable of being lowered through the pump tubing string isv also capable of passing through the seat for the standing valve assembly into the well upon removal of the standing valve assembly through the pump tubing string. Consequently, various well repairing and reconditioning operations may be carried out without removing the tubing system from the well, which is an important feature of the invention.

Another object of the invention is to provide a standing valve assembly carrying a radially extensible and retract able latch means which is engageable with the seat for the standing valve assembly to support the standing valve assembly in its operating position when such latch means is extended, the standing valve assembly being freely movable between its seat and the surface when the latch means is retracted. With this construction, the inside diameter of the annular seat for the standing valve assembly may Califi, assignor to a Patented Sept. 13, 1950 be substantially equal to the outside diameter of the standing valve assembly itself, since the latch means is extensible radially outwardly into engagement with the annular seat to support the standing valve assembly, and may be substantially equal to the inside diameter of the pump tubing string to permit the passage through the annular seat of any repairing or reconditioning equipment for the well which is capable of passing through the pump tubing string itself, which is an important feature of the invention.

' Another object is to provide a latch means comprising circumferentially spaced latch elements having upper and lower ends and pivotally connected to the standing valve assembly adjacent their upper ends so that the lower ends thereof may swing inwardly and outwardly between retracted and extended positions, the lower ends of such latch elements being engageable with the annular seat for thestanding valve assembly to support such assembly in its operative position. The latch means further includes spring means for biasing the latch elements outwardly so as to bias the lower ends thereof outwardly toward their extended positions.

A further object of the invention is to make the length of the latch elements greater than the maximum spacing between tubing ends within couplings interconnecting the tnbings forming the pump tubing string so that the lower ends'of the latch elements will not hang up on the upper ends of the tubings as they pass through the couplings. A related object is to provide the latch elements with beveled external surfaces adjacent the lower ends thereof and to provide the upper ends of the tubings within the couplings with beveled inner surfaces to further minimize any possibility of the standing valve assembly hanging up as it is moved downwardly through the pump tubing string.

Another object of the invention is to provide an annular clearance 'above the annular seat for the standing valve assembly which has an axial length exceeding the length of the latch elements so that the latch elements may move radially outwardly into supporting engagement with the annular seat when the standing valve assembly reaches its operating position, or, more accurately, a point just above its operating position.

An additional object ofthe invention is to provide the standing valve assembly with an external annular sealing means, such as an O-ring, which is engageable with the peripheral wall of a bore through a sealing collar into Which at least the lower portion of the standing valve assembly is insertable, this annular sealing means thus preventing fluid communication between the pump tubing string and the well externally of the standing valve assembly.

Another object is to provide a structure wherein the annular seat for the standing valve assembly is formed by the upper end of the sealing collar, the annular sealing means being carried by the standing valve assembly below the latch elements.

Another object of the invention is to provide on the standing valve assembly surfaces which are engageable by the upper ends of the latch elements and which slope downwardly toward the axis of the standing valve assembly at a predetermined 'angle, and to provide an annular seat for the standing valve assembly which slopes downwardly'toward its axis at an angle no greater than such predetermined angle. With this construction, the latch elements act as struts the upper ends of which are seated against the mentioned surfaces of the standing valve assembly and the lower ends of which are seated against the annular seat for the standing valve assembly, the aforementioned relation between the downward slope of such surfaces and the downward slope of the annular seat insuring that there is no tendency to cam the latch elements inwardly into their retracted positions under load. Consequently, there is no possibility that the latch elements will pass downwardly through the sealing collar as long as they are in their extended positions.

Another object of the invention is to provide the standing valve assembly above the lower ends of the latch elements with an annular shoulder which has a diameter slightly greater than the inside diameter of the annular seat so that the standing valve assembly will not drop through the sealing collar in the event that the latch elements fail to extend for some reason, such as failure of the spring means for extending them. The inside diameter of the annular seat needs to be only a few thousandths of an inch less than the outside diameter of the annular shoulder on the standing valve assembly so that the annular seat does not significantly reduce the diameter of well repairing or reconditioning equipment to be lowered into the well through the pump tubing string and the annular seat for the standing valve assembly.

Another object is to provide the standing valve assembly with an axial bore adjacent its upper end which is encircled by an upwardly facing, annular pump seat and a downwardly facing, annular shoulder below the pump seat, this bore being adapted to receive an expansible and contractible mandrel on a tool for installing the standing valve assembly, or a tool for retrieving it when removal from the well is desired. A related object is to provide such tools each having an upper head engageable with the pump seat on the standing valve assembly and another head at the lower end of the expansible and contractible mandrel which is engageable with the annular shoulder within the standing valve assembly, the distance between the two heads on each tool being slightly in excess of the distance between the pump seat and the internal annular shoulder mentioned.

Another object is to provide a standing valve assembly wherein the internal annular shoulder discussed in the preceding paragraph converges downwardly and wherein the head on the expansible and contractible mandrel of the tool for installing the standing valve assembly is provided with a shoulder which is engageable with the internal annular shoulder on the standing valve assembly, but which converges upwardly. Consequently, the head on the expansible and contractible mandrel can readily be disengaged from the internal annular shoulder on the standing valve assembly when it is desired to remove the installing tool after installation of the standing valve assembly.

The foregoing objects, advantages, features and results of the present invention, together with various other objects, advantages, features and results thereof which will be evident to those skilled in the art in the light of this disclosure, may be attained with the exemplary embodiments of the invention described in detail hereinafter and illustrated in the accompanying drawings, in which:

Fig. 1 is a view, partially in elevation and partially in vertical section, illustrating a fluid operated, free pump system which embodies the invention;

Figs. 2, 3 and 4 are enlarged, fragmentary, transverse sectional views respectively taken along the arrowed lines 2-2, 3-3 and 4-4 of Fig. 1;

Figs. 5 and 6 are fragmentary, vertical sectional views respectively taken along the arrowed lines 5-5 and 6--6 of Figs. 2 and 4, respectively;

Fig. 7 is a fragmentary, vertical sectional view on an enlarged scale which is similar to a portion of Fig. 6;

Figs. 8 and 9 are transverse sectional views respectively taken along the arrowed lines 88 and 9-9 of Fig. 7;

Fig. 10 is a fragmentary, vertical sectional view illustrating one embodiment of an installing tool of the invention in use to run into the well a standing valve assembly of the invention past a coupling in a pump tubing string, another embodiment of an installing tool of the invention being shown in Figs. 5 and 6; and

Fig. 11 is a fragmentary, vertical sectional view illustrating a retrieving tool of the invention in use to retrieve the standing valve assembly thereof.

As a matter of convenience, the present invention is illustrate-d in the drawings as incorporated in a fluid 0p erated, free pump system in which the production fluid discharged by the pump and the spent operating fluid dischargedthereby are conveyed to the surface separately, and which is thus a so-called closed system. Also as a matter of convenience, the invention is illustrated in the drawings in conjunction with a fluid operated, free pump system which includes a fluid operated, free pump and an engine valve for controlling the pump as separate units in accordance with my copending patent application Serial No. 598,785, filed July 19, 1956, the disclosure of which is incorporated herein by reference. However, it will be understood that the present invention is by no means limited to a closed system, nor to the separate pump and valve system of the copending-application just mentioned, being usable in an open system-and in a fluid operated, free pump system wherein'the pump and the valve are incorporated in a single unit, as well.

Refer-ring particularly to Fig. l of the drawings, the present invention is illustrated therein as incorporated in a closed, fluid operated, free pump system installed in a well which is provided with a casing 20 having perforations 22 through which well fluid may flow from a surrounding productive formation, not shown. At the upper end of the casing 2!) is a casing head 24 from which supply, return and production tubing strings 26, 28 and 30 are suspended. The supply string 26 is adapted to conduct operating fluid under pressure downwardly into the well while the return string 28 is adapted to convey spent operating fluid upwardly to the surface, production fluid pumped from the well being conveyed upwardly to the surface through the production string 30. The supply, return and production strings 26, 28 and 30 are connected at their upper ends to a control device '32 which also has connected thereto supply, return and production lines 34, 36 and 38. The supply line 34 is connected to a suitable source of operating fluid under pressure, such as surface pumping equipment, not shown, while the return and production lines 36 and 38 are connected to suitable points of disposal, not shown, for the spent operating fluid and the production fluid. The control device 32 is provided therein with a selector valve means, not shown, actuable by a handle 40 for interconnecting the supply, return and production strings 26, 28 and 30 and the supply, return and production lines 34, 36 and 38 in various relationships to perform functions which will be described hereinafter.

The supply, return and production strings 26, 28 and 30 are connected at their lower ends to a packer collar 42, the production string being connected thereto through an enlarged coupling 39 and an upper pump housing tube 41. Depending from the packer collar 42. is a lower pump housing tube 44 connected at its lower end to a bottom shoe 4,6, the collar 39 and the pump housing tubes 41 and 44 forming a downward extension of the production string 30. A fluid operated, free pump unit 48 is movable between the surface and an operating position in the well through the production string 30, the latter being sometimes referred to herein as a pump tubing string for this reason. When the pump unit 48 is in its operating position in the well, it is seated on a standing valve installation 50 of the invention which will be described hereinafter.

The pump unit 43 is controlled by an engine valve unit 52 which is movable between the surface and an operating position in the well through the supply string 26. When the valve unit is in its operating position, it is housed Within the packer collar 42 opposite the engine section of the pump unit 48.

Interconnecting the packer collar 42 and the bottom shoe 46 is a tube 54 which, in effect, forms a downward extension of the supply string 26. Also interconnecting thepacker collar 42 and the bottom shoe 46 is a tube 56 which, in eflect, forms a downward extension of the return string '28. The tube 54, as shown in Fig. 6, communicates with an axial bore 58 in the bottom shoe 46 which, in turn, communicates with the interior of a liner 60 in the bottom shoe through a passage designated generally by the numeral 62. Similarly, the tube 56 communicates with an axial bore 64 in the bottom shoe 46 which communicates with the interior of a liner 66 below and coaxial with the liner 60 through a passage designated generally by the numeral 68.

The over-all operation of the foregoing fluid operated, free pump system is described in detail in my aforementioned copending application Serial No. 598,785 so that a complete description herein is unnecessary. Briefly, with the handle 40 of the control device 32 in one position, the supply, return and production lines 34, 36 and 38 are connected to the supply, return and production strings 26, 28 and 30, respectively, whereby operating fluid under pressure is delivered to the pump and valve units 48 and '52 through the supply string 26 to operate such units. At the same time, spent operating fluid is returned to the surface throughthe return string 28 and is discharged into the return line 36, production fluid pumped by the pump unit 48 being conveyed to the surface through the production string 30 and being discharged into the production line 38.

When installing the pump and valve units 48 and 52, which may be done simultaneously, the handle 40 of the control device 32 is set in a position to connect the supply line 34 to both the supply and production strings 26 and 30 with the valve such strings. Consequently, the operating fluid under pressure derived from the supply line 34 displaces the pump and valve units 48 and 52 downwardly into their operating positions hydraulically. The pump and valve units 48 and 52 may also be run in separately, as more fully discussed in my copending application Serial No. 598,785.

The pump and valve units 48 and 52 may be circulated out of the well at the same time by setting the handle 40 of the control device 32 in a position to connect the supply line 34 to the return string 28. Under these conditions, operating fluid under pressure is conveyed downwardly through the return string 28, the tube 56, the bore 64, and the passage 68 and acts on the lower end of the pump unit 48, as will be clear from Fig. 7, to displace this unit upwardly. The operating fluid under pressure supplied to the return string 28 to move the pump unit 48 upwardly also acts on the lower end of the valve unit 52 in a manner not specifically shown, but completely disclosed in my copending application Serial No. 598,785, to move the valve unit upwardly to the surface. As also disclosed in detail in the copending application just mentioned, the pump and valve units 48 and 52 may be circulated to the surface independently of each other by utilizing appropriate settings of the handle 40 of the control device 32.

Turning now to a consideration of the standing valve installation 50 with particular reference to Figs. 6 to 9 of the drawings, the bottom shoe 46 has threaded thereinto in alignment with the production string 30 an inlet tube 70 which co-operates with the bottom shoe to provide a housing forming a chamber 71 fora standing valve assembly 72 of the invention. The standing valve assembly 72 includes a shoe 74 provided at its upper end with an upwardly facing, annular, downwardly, converging, pump seat 76 on which the inlet end of the fluid operated pump unit 48 is seated, as shown in Fig. 7, when such pump unit is in its operating position. The shoe 74 is provided with an axial bore 78 therethrough the upper end of which is encircled by the pump seat 76 and the lower end of which is encircled by a downwardly facing, annular, downwardly converging shoulder 80, best shown in Figs. and 11. Threaded onto the lower end of the and pump units inserted into.

shoe 74 is a tube 82 into the lower end of which is threaded a tubular inlet fitting 84. Within the tube 82 is p a standing valve 86 engageable with an upwardly facing,

annular standing valve seat 88. Also located within the tube 82 is a magnet 90 for normally holding the standing valve 86, which is formed of magnetizable material, off its seat when the pump unit 48 is in operation, any backflow of fluid into the well moving the standing valve 86 downwardly into engagement with its seat 88 in opposition to the action of the magnet 90, however. A sleeve 92 nonmagnetizable material around the magnet 90 prevents direct contact between the standing valve 86 and the magnet, as more fully disclosed in my copending application' Serial No. 527,971, filed August 12, 1955.

As will be apparent, the standing valve assembly 72 permits upward flow of fluid from the well into the inlet of the fluid operated pump unit 48. However, when any tendency toward backflow into the well occurs, the standing valve 86 is moved downwardly into engagement with its seat 88 to prevent such backflow.

In order to drain the tubing system composed of the supply, return and production strings 26, 28 and 30 when removal of the standing valve assembly 72 is to be effected, as will be discussed hereinafter, the standing valve assembly is provided with a frangible drain element or fitting in the form of a hollow knockout plug 94 threaded into the tube 82 and extending into the interior thereof so that its inner end may be broken olf by a knockout bar, not shown, or by the lower end of a retrieving tool for the standing valve assembly which will be described hereinafter.

Considering how the standing valve assembly 72 is supported and sealed in its operating position in a manner to prevent any restriction to passage of well repairing or reconditioning equipment downwardly through the production string 30 into the well, a sealing collar 96 coaxial with the production string 30 and the inlet tube 70 is disposed within the bottom shoe 46 and is clamped between an annular shoulder 98 on the bottom shoe and the upper end of the inlet tube. The sealing collar 96 is sealed with respect to the bottom shoe 46 by an O-ring 100 carried in an external annular groove in the sealing collar. The sealing collar 96 is provided with an axial bore 102 there through into which the lower portion of the standing valve assembly 72 is insertable and the diameter of which is only slightly less than the inside diameter of the production string 30 so that well reconditioning or repairing equipment which can pass through the production string can also pass through the sealing collar 96 into the well. The standing valve assembly 72 is sealed with respect to he sealing collar 96 by an annular sealing means shown as comprising an O-ring 104 disposed in an external annular groove in the shoe 74 and engageable with the peripheral wall of the bore 102 through the sealing collar.

The sealing collar 96 is provided at its upper end with' an annular, upwardly facing, downwardly converging seat 106 for the standing valve assembly 72. The standing valve assembly 72 is supported on the seat 106 by an extensible and retractable latch means 103 carried by the shoe 74 of the. standing valve assembly, this latch means, when extended, engaging the seat 106 to prevent downward movement of the standing valve assembly through the sealing collar 96. As a precautionary measure to prevent loss of the standing valve assembly 72 in the well, the shoe 74 thereof is provided with an annular rib located above the O-ring 104 and providing a downwardly facing annular shoulder engageable with the seat 106 to stop downward movement of the standing valve assembly in the event of malfunctioning of the latch means 108 for any reason. The diameter of the bore 102 needs to be only a few thousandths of an inch less than the outside diameter of the rib 110 to accomplish the foregoing. Consequently, the diameter of the bore 102 is not significantly less than tion string 30. Thus, any well reconditioning or repairing the inside diameter of the producequipment which will pass through the production string 30 with adequate clearances will also pass through the sealing collar 96 into the well.

Considering the latch means 108 in more detail, the shoe 74 of the standing valve assembly 72 is provided with circumferentially spaced recesses 112 into which latch elements 114 are retractable, there being three recesses and latch elements in the particular construction illustrated, although this number may be varied. The latch elements 114 have lower ends 116 engageable with the seat 106 and have upper ends 118 engageable with surfaces 120 of the shoe 74 which form the upper ends of the recesses 112 therein.

As will be apparent, the latch elements 114 are, in effect, braces or struts which act in compression between the surfaces 120 and the seat 106 to support the standing valve assembly 72 in its operating position with the O-ring 104 in sealing engagement with the wall of the bore 162 through the sealing collar 96. In order to avoid any tendency of the lower ends 116 of the latch elements 114 to be cammed inwardly out of engagement with the seat 106 as the result of the application of a downward pressure force to the standing valve assembly 72 during operation of the pump unit 48, or at any other time, the ends 116 and 118 of each latch element 114, the portion of the seat 106 engaged by the lower end 116 thereof, and the surface 120 engaged by the upper end thereof are preferably all parallel, the surfaces 120 sloping inwardly and downwardly at the same angle as the seat 1%. Under these conditions, a downward pressure force applied to the standing valve assembly 72 produces no tendency to cam the lower ends 116 of the latch elements 114 either inwardly or outwardly. If there is any deviation from this balanced condition, it is preferably in a direction such that downward pressure force applied to the standing valve assembly 72 earns the lower ends 116 of the latch elements 114 outwardly, rather than inwardly. Thus, the important thing is that the angle of downward and inward inclination of the seat 1116 must be no greater than the angle of downward and inward inclination of the surfaces 121 In other words, the angle of the seat 1116 may be flatter than that of the surfaces 120, but must not be steeper than the angle of these surfaces.

The latch elements 114 are pivotally connected to the shoe '74 in such a manner that the lower ends 116 thereof are swingable inwardly and outwardly between retracted and extended positions, the latch elements being disposed within the recesses 112 when retracted and the lower ends thereof being engageable with the seat 106 in the manner hereinbefore described when extended. As best shown in Figs. 7 and 8, each latch element 114 is pivotally connected to the shoe 7 4 by a pin 122, such pin being located adjacent the upper end 118 of the latch element and adjacent the inner side thereof so that the upper end 118 of such latch element pivots into and out of engagement with the corresponding surface 120 as the latch element pivots into its extended position, or toward its retracted position, as will be clear from a comparison of Fig. 7 with either Fig. 10 or Fig. 11 of the drawings. Additionally, the latch elements 114 fit loosely on the pins 122 so that the upper and lower ends 118 and 116 thereof can bear against the surfaces 120 and the seat 106 properly.

The latch elements 114 are biased outwardly into their extended positions by torsion springs 1'24 coiled around the respective pins 122, each spring having an arm 126 inserted into the corresponding latch element 114 and an arm 128 adapted to bear against the inner wall of the corresponding recess 112. The inner side of each latch element 114 is provided with a recess 131 therein to receive the corresponding spring arm 128 when such latch element is in its fully retracted position.

In order to prevent the lower ends 116 of the latch elements 114 from hanging up on upwardly facing annular shoulders between the surface of the ground and the seat 106 as the standing valve assembly 72 is run in, each 8 such shoulder either converges downwardly at a very steep angle, as typified by the shoulder 132 in Fig. 5, or each such shoulder is spaced downwardly from a downwardly facing annular shoulder of about the same insidediameter a distance less than the length of the latch elements 114 and is provided with a beveled inner edge, as typified by the upwardly and downwardly facing annular shoulders 134 and 136 in Fig. 5, or as typified by the upwardly and downwardly facing annular shoulders 138 and 140 in Fig. 10. In order to further minimize any possibility of hang up as the standing valve assembly 72 is run in, eled adjacent the lower ends 116 thereof, as indicated by the numeral 142.

In Fig. 10 of the drawings, the standing valve assembly 72 is shown being run in through a coupling 144 which interconnects two tubings 146 making up part of the production tubing string 30. The shortest length for the latch elements 114 which can be used must exceed the maximum spacing of the tubing ends within each coupling which is permitted by make-up tolerances. As shown in Fig. 10, the length of the latch elements 114 exceeds the spacing of the annular shoulders 138 and 140 formed by the ends of the tubings 146. As Fig. 10* clearly shows, the upper tubing 146 still engages the latch elements 114 when the lower ends 116 thereof encounter the upwardly facing annular shoulder 138 formed by the upper end of the lower tubing 146 to hold the lower ends of the latch elements inwardly sufficiently that they do not hang up on the shoulder 138, the bevels 142 on the latch elements and the beveled inner edge of the shoulder 133 further preventing any possibility of hanging up. Thus, the standing valve assembly 72 may be run in freely despite variations in the inside diameter of the production string 30, or other structures through which the standing valve assembly must pass before the lower ends 116 of the latch elements 114 encounter and seat on the seat 106. As Fig. 7 clearly shows, there is an unobstructed space above the seat 1% of an axial length atleast equal to the length of the latch elements 114 so that these latch elements are free to move outwardly into engagement with the seat 106.

In pulling the standing valve assembly 72 out of the well, there is little or no tendency for the latch elements 114 to hang up on any downwardly facing annular shoulders which may be present since engagement of the latch elements with such annular shoulders automatically swings the latch elements inwardly toward their retracted positions. To assist in camming the latch elements 114 inwardly when they engage downwardly facing annular shoulders as the standing valve assembly 72 is pulled out, the outer sides of the latch elements may be beveled adjacent the upper ends 118 thereof, as indicated at 148.

Considering now how the standing valve assembly 72 is run into the well, and referring particularly to Fig. 10 of the drawings, the invention provides an installation tool 150 having thereon an upper head 152 which is complementary to and engageable with the pump seat 76 at the upper end of the shoe 74 of the standing valve assembly. Depending from the upper head 152 is an expansible and contractible mandrel 154 which is similar to a collet chuck and which is insertable through the bore 78 in the shoe 74. This mandrel terminates at its lower end in a lower head 156 having an upwardly facing annular shoulder 158 on which the downwardly converging annular shoulder 80 is adapted to seat to support the standing valve assembly 72, and which converges upwardly so that the mandrel 154 may contract readily to disengage the annular shoulder 158 from the annular shoulder 80 to permit removal of the installation tool 150, leaving the standing valve assembly 72 in its operating position.

Considering the manner in which the standing valve assembly 72 is run into the well with the installation tool 150 shown in Fig. 10 of the drawings, the standing the outer sides of the latch elements 114 are bev valve assembly and the tool are lowered through the production string 30 by means of a wire line 160 connected to the tool. After the standing valve assembly 72 has been lowered into its operating position, the tubing system may be filled with fluid so that the head of fluid above the standing valve assembly holds it in place with the lower ends 116 of the latch elements 114 in engagement with the seat 106. The installation tool 150 may then be withdrawn by means of the wire line 160, the upwardly converging annular shoulder 158cm the lower head 156 of the tool forcing the mandrel 154 to contract to permit withdrawal of the mandrel from the bore 78 through the shoe 74 of the standing valve assembly. I

In o-rder to prevent breaking the knockout plug 94 as the standing valve assembly 72 is run in, the distance between the pump seat 76 and the knockout plug is greater than the distance between the upper head 152 and the lower end of the lower head 156 so that, when the upper head 152 is in engagement with the pump seat 76, the lower head 156 is above the knockout plug.

The standing valve assembly 72 may also be run in and the installation tool removed hydraulically with the structure shown in Figs. and 6 of the drawings. In this structure, the numeral 162 designates an installation tool which includes the same upper head 152, expansible and cont-ractible mandrel 154, lower head 156 and annular shoulder 158 as the installation tool 150. In this case, the installation tool 162 is, in eflfect, a dummy pump unit similar in external configuration to the pump unit 48, and is provided adjacent its lower end with O-rings 164 capable of fluid-tight engagement with the liner 60 above the passage 68. The tool 162 is provided adjacent its upper end with a packer mandrel 166 similar to the packer mandrel with which fluid operated free pumps are conventionally provided, the packer mandrel 166 carrying one or more downwardly facing packer cups 163 adapted to engage the production string 30 in a fluid-tight manner. The single packer cup 168 shown in Fig. 5 of the drawings is shown as being disposed in the enlarged coupling 39 when the installation tool 162 is in engagement with the standing valve assembly 72 with the latter in its operating position, the packer cup 168 thus occupying the same position under such conditions as a packer cup 170 on a packer mandrel 172, Fig. l, of the pumpu'nit 48 when the pump unit is in its operating position wherein it is seated on the standing valve assembly.

In order to run the standing valve assembly 72 into the well with the installation tool 162, the standing valve assembly and the tool are interengaged in the manner shown and are lowered into the production string 36 and are circulated downwardly therein by setting the handle 4%) of the control device 32 in a position to deliver operating fluid under pressure from the supply line 34 to the production string 30 above the installation tool 162. This hydraulic circulation of the standing valve assembly 72 and the installation tool 162 into the well continues until the standing valve assembly is in its operating position. The tubing system may then be completely filled with fluid, the head of fluid above the standing valve assembly 72 then holding the standing valve assembly in place. By setting the handle 40 of the control device 32 in a position such that the control device c-loses the upper end of the supply string 26, connects the return string 28 to the supply line 34, and connects the production string 30 to the production line 38, operating fluid under pressure from the supply line 34 passes through the control device 32, the return string 28, the tube 56, the bore 64 in the bottom shoe 46, and the passage 68 to a point beneath the =O-rings 164 on the installation tool 162. Consequently, the operating fluid under pressure acts downwardly on an annular area of the standing valve assembly 72 to assist in holding it in place, and acts upwardly on an annular area of the installation tool 162 to disengage it from the standing valve assembly in the manner hereinbefore described in connection with the installation tool 150. By the time that the 'O-rings 164 clear the upper end of the liner 60, the packer cup or cups 168 are within the production string 30 so that continued delivery of operating fluid under pressure below the instalation tool 162 results in circulation thereof to the surface for removal.

Thus, the standing valve assembly 72 may be run in and the installation tool removed either hydraulically, or by means of the wire line 160.

Referring to Fig. 11 of the drawings, illustrated therein is a retrieving tool 174 for removing the standing valve assembly 72 from the well. Before running in the retrieving tool 174, the knockout plug 94 may be broken to drain the tubing bar, not shown, lowered into the Well through the production string 30. Alternatively, the retrieving tool 174 itself may be utilized to break the knockout plug 94, as will be described.

The retrieving tool 174 is similar to the installation tool and includes an upper head 176 engageable with the pump seat 76 and an expansible and contractible mandrel which is insertable through the bore 78 in the shoe 74. The mandrel 178 terminates in a lower head 180 which is engageable with the knockout plug 94 to break it, the distance between the knockout plug 94 and the pump seat 76 being less than the distance between the upper head 176 and the lower end of the lower head 180 so that the lower head engages the knockout plug 94 to break it before the upper head 176 engages the pump seat 76.

The lower head 180 is provided with an upwardly facing, annular shoulder 182 which converges downwardly at about the same angle as the shoulder 80 on the shoe 74 so that hook-like engagement between the shoulders 80 and 182 results to prevent disengagement of the standing valve assembly 72 from the retrieving tool 174 as the latter is displaced upwardly to the surface. In effect, the shoulders 80 and 182 cam the segments of the expansible and contractible mandrel 178 outwardly to prevent contraction of the mandrel, and thus disengagement of the standing valve assembly 72 and the tool 174. The retrieving tool 174 is lowered into the well and is withdrawn therefrom with the standingvalve assembly 72 by means of a wire line 184.

An important feature of the present invention is that the latching elements 114 may be provided in several different lengths so that the O-ring 104 on the standing valve assembly 72 may be located in diiferent positions relative to the wall of the bore 102 through the sealing collar 96 to compensate for wear, such wear of the sealing collar resulting from cutting thereof by sand particles, or the like, carried by leakage past the O-ring 104. Preferably, the shortest latch elements 114 are used first to locate the O-ring 104 near the bottom of the sealing collar 96 initially. If cutting of the sealing collar 96 occurs at this lowest position of the O-ring 104, the O-ring position can be raised by removing the standing valve assembly 72 from the well, installing a set of longer latch elements 114, and then rerunning the standing valve assembly. This procedure is repeated until the length of the latch elements 114 is increased to the maximum possible, which locates the O-ring 104 adjacent the upper end of the sealing collar. In this way, the same sealing collar 96 may be used for a long period of time without the necessity of pulling the tubing system to replace it.

Although I have disclosed exemplary embodiments of my invention herein for illustrative purposes, it will be understood that various changes, modifications and substitutions may be incorporated in such embodiments without departing from the spirit of the invention as defined by the claims which follow.

I claim:

1. In combination: a standing valve assembly having upper and lower ends and having a passage therethrough system by means of a knockout 1 1 extending from its lower end to ing valve assembly including an upwardly facing, annular pump seat adjacent its upper end which encircles said passage, and said standing valve assembly including below said pump seat an annular valve seat encircling said passage and a standing valve engageable with said valve seat; annular sealing means carried by said standing valve assembly externally thereof and below the upper end thereof; and extensible and retractable latch means carried by said standing valve assembly below the upper end thereof and above said annular sealing means, said latch means including circumferentially spaced latch elements having upper and lower ends and including means pivotally connecting said latch elements to said standing valve assembly adjacent their upper ends so that the lower ends thereof are movable inwardly and outwardly between retracted and extended positions, said latch means further including spring means biasing said latch elements outwardly so as to bias the lower ends thereof toward their extended positions.

2. In combination: a standing valve assembly having upper and lower ends; a housing providing a chamber into which said standing valve assembly is insertable; a sealing collar carried by said housing and having a bore therethrough coaxial with said chamber, said sealing collar being provided with an upwardly facing, annular seat, the outside diameter of at least the lower portion of said standing valve assembly being less than the diameter of said bore so that said portion of said standing valve assembly is insertable into said bore; annular sealing means carried by said portion of said standing valve assembly below the upper end of said standing valve assembly and engageable with the peripheral wall of said bore when said portion of said standing valve assembly is inserted into said bore; and extensible and retractable latch means carried by said standing valve assembly above said sealing means and engageahle with said seat when extended to support said standing valve assembly with said portion thereof within said bore.

3. A combination as set forth in claim 2 including an external annular shoulder on said standing valve assembly above said sealing means and engageable with said seat to support said standing valve assembly in the event of failure of said latch means to engage said seat.

4. In combination: a standing valve assembly having upper and lower ends; a housing providing a chamber into which said standing valve assembly is insertable; a sealing collar carried by said housing and having a bore therethrough coaxial with said chamber, said sealing collar being provided with an upwardly facing, annular seat, the

its upper end, said stand outside diameter of at least the lower portion of said standing valve assembly being less than the diameter of said bore so that said portion of said standing valve assem bly is insertable into said bore; annular sealing means carried by said portion of said standing valve assembly below the upper end of said standing valve assembly and engageable with the peripheral wall of said bore when said portion of said standing valve assembly is inserted into said bore; and extensible and retractable latch means carried by said standing valve assembly above said sealing means and engageable with said seat when extended to support said standing valve assembly with said portion thereof within said bore, said latch means including circumferential'ly spaced latch elements having upper and lower ends and including means pivotally connecting said latch elements to said standing valve assembly adjacent their upper ends so that the lower ends thereof are movable inwardly and outwardly between retracted and extended positions, said lower ends of said latch elements being engageable with said seat when in said extended positions, said latch means including spring means biasing said latch elements outwardly so as to bias said lower ends thereof toward said extended positions.

5. A combination as set forth in claim 4 wherein said standing valve assembly is provided with circumferentially spaced surfaces which are engageable by said upper ends of said latch elements and which slope downwardly toward the axis of said standing valve assembly at a predetermined angle, said seat sloping downwardly toward the axis of said bore at an angle no greater than said predetermined angle.

6. A combination as set forth in claim 4 wherein said latch elements have beveled external surfaces adjacent said lower ends thereof.

7. A combination as set forth in claim 4 wherein said housing is connected to the lower end of a tubing string which includes tubings interconnected by couplings, the tubing ends within each of said couplings being spaced apart, the length of said latch elements exceeding the spacing between the tubing ends in each coupling.

References Cited in the file of this patent UNITED STATES PATENTS 

